[Bug c++/95615] [coroutines] Coroutine frame and promise is leaked if exception thrown from promise.initial_suspend()

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95615

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Iain D Sandoe <iains@gcc.gnu.org>:

https://gcc.gnu.org/g:fe55086547c9360b530e040a6673dae10ac77847

commit r11-7527-gfe55086547c9360b530e040a6673dae10ac77847
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Mon Feb 15 15:09:27 2021 +0000

    coroutines : Handle exceptions throw before the first await_resume()
[PR95615].

    The coroutine body is wrapped in a try-catch block which is responsible for
    handling any exceptions thrown by the original function body.  Originally,
the
    initial suspend expression was outside this, but an amendement to the
standard
    places the await_resume call inside and eveything else outside.

    This means that any exception thrown prior to the initial suspend
expression
    await_resume() will propagate to the ramp function.  However, some portion
of
    the coroutine state will exist at that point (how much depends on where the
    exception is thrown from).  For example, we might have some frame parameter
    copies, or the promise object or the return object any of which might have
a
    non-trivial DTOR.  Also the frame itself needs to be deallocated. This
patch
    fixes the handling of these cases.

    gcc/cp/ChangeLog:

            PR c++/95615
            * coroutines.cc (struct param_info): Track parameter copies that
need
            a DTOR.
            (coro_get_frame_dtor): New helper function factored from
build_actor().
            (build_actor_fn): Use coro_get_frame_dtor().
            (morph_fn_to_coro): Track parameters that need DTORs on exception,
            likewise the frame promise and the return object.  On exception,
run the
            DTORs for these, destroy the frame and then rethrow the exception.

    gcc/testsuite/ChangeLog:

            PR c++/95615
            * g++.dg/coroutines/torture/pr95615-01.C: New test.
            * g++.dg/coroutines/torture/pr95615-02.C: New test.
            * g++.dg/coroutines/torture/pr95615-03.C: New test.
            * g++.dg/coroutines/torture/pr95615-04.C: New test.
            * g++.dg/coroutines/torture/pr95615-05.C: New test.